Re: weird sum() results - Mailing list pgsql-general

From Mark Dalphin
Subject Re: weird sum() results
Date
Msg-id 3887C06F.5D661E@amgen.com
Whole thread Raw
In response to weird sum() results  (Hitesh Patel <hitesh@presys.com>)
List pgsql-general
On Wed, 19 Jan 2000 16:33:06, Hitesh Patel wrote:


> I have a table with a filed named 'amount' and all the values are
>
> positive values, but if i do this:
>
>         select sum(amount) from table where state = 'CA';
>
> I get a negative number.  Doing a
>
>         select name, amount from table where state = 'CA' and amount < '0';
>
> Returns 0 rows.  Any ideas as to why i'm getting a negative value for
> the sum()?
>

If the sum() is larger than the largest possible integer, the values will "wrap around" into the negative
integers. I don't know how many values you are adding, but, assuming you are storing your amount as an
'int4', your sum will wrap at about 2 billion (2,147,483,647).

HTH,
Mark

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